Various golf balls for the practice at the places rather than standard golf training courses have been disclosed, and have appeared on the market. FIG. 1 shows a golf training ball according to the prior art. This structure of golf ball is molded from plastic, having a hollow, slotted, spherical body. There is also known another structure of golf training ball which is molded from high-density rubber sponge in a solid state. The conventional golf training balls have various drawbacks as outlined hereinafter:
(1) Short service life. The said hollow, plastic golf training ball have weak structure strength and low shock absorbing ability, and tend to break down upon a heavy strike. The said solid high-density rubber sponge golf training ball tend to break after several hits (about 30 hits on an average). PA1 (2) Low coefficient of safety. When a plastic golf training ball hits a person or an object, the rigid outer shell of the ball will cause a severe damage to the person or the object. The injury will be more serious if the ball is broken. A high-density sponge golf training ball has relatively high density and its shock absorbing ability is still low, therefore it will cause a hurt when hitting or bouncing to hit a person. PA1 (3) High noise. Because regular golf training balls have low shock absorbing ability, they will produce a big noise when hit. PA1 (4) Being pollutive. Regular golf training balls wear quickly with use, and are not reclaimable when damaged. The cost of the disposal of wasted golf training balls is high. PA1 (1) Having a solid structure of proper density. Because regular hollow, plastic golf training balls have a light mass, they do not fly in the track they should have when hit. Regular high-density rubber sponge golf training balls have a heavy mass, and will cause an injury when it hits a person. If to reduce the mass of a solid rubber sponge golf training ball, it tends to be easily deformed and its service life will be relatively shortened. PA1 (2) Having a soft peripheral structure, a density gradually decreased from the center toward the periphery. This arrangement facilitates the practicing of spin, produces low noise when hit, and can buffer the impact force when the ball hits a person or an object. PA1 (3) Being durable and repairable. Using durable golf training balls greatly saves the training cost, and reduces the possibility of polluting the environment.
In view of the aforesaid problems, a good golf training ball shall meet the following requirements: